U.S. patent number 4,273,124 [Application Number 06/044,582] was granted by the patent office on 1981-06-16 for nasal cannula.
Invention is credited to J. Earl Zimmerman.
United States Patent |
4,273,124 |
Zimmerman |
June 16, 1981 |
Nasal cannula
Abstract
A nasal cannula of the type to be connected to a fluid duct and
positioned within the nose of a patient for administering
therapeutic fluid. The cannula comprises a resilient bulbous member
configured to fit snugly within and against the vestibule wall of
one nasal cavity of the patient to form a tight seal with respect
thereto while maintaining the other nasal cavity in communication
with ambient surroundings. The bulbous member includes a passage
therethrough for communicating the fluid duct with the nasal cavity
so that fluid supplied through the duct is inhaled through the one
nasal cavity and exhaled through the other nasal cavity and/or open
mouth.
Inventors: |
Zimmerman; J. Earl (Pine Grove,
PA) |
Family
ID: |
21933161 |
Appl.
No.: |
06/044,582 |
Filed: |
June 1, 1979 |
Current U.S.
Class: |
128/207.18;
604/94.01 |
Current CPC
Class: |
A61M
16/0666 (20130101) |
Current International
Class: |
A61M
16/06 (20060101); A61M 003/00 () |
Field of
Search: |
;128/245,246,349B,240,241,250 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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321688 |
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Jun 1920 |
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DE2 |
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178630 |
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Apr 1922 |
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GB |
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532214 |
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Jan 1941 |
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GB |
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Primary Examiner: Yasko; John D.
Attorney, Agent or Firm: Burns, Doane, Swecker &
Mathis
Claims
What is claimed is:
1. A breathing apparatus comprising a source of pressurized
therapeutic gas, a nasal cannula directly connected to said gas
source and positioned within the nose of a patient to administer
the gas to the patient, said cannula comprising a resilient
enlarged member configured to fit snugly against the vestibule wall
of one nasal cavity of the patient to form a tight seal with
respect thereto while maintaining the other nasal cavity in
communication with ambient surroundings, said enlarged member
including a passage therethrough for communicating the gas with the
nasal cavity so that the gas supplied from said source is inhaled
solely through said one nasal cavity and into the patient's lungs
and exhaled solely through said other nasal cavity and/or open
mouth of the patient.
2. Apparatus according to claim 1, wherein said enlarged member
comprises a bulbous member of generally spherical
configuration.
3. Apparatus according to claim 2, wherein said passage extends
centrally through said bulbous member and terminates at an outer
wall thereof.
4. Apparatus according to claim 1, wherein said cannula includes a
second enlarged member to be positioned snugly within said other
nasal vestibule and placed in communication with the ambient
surroundings.
5. Apparatus according to claim 1, wherein said passage includes
two inlets communicating with the gas source.
6. Apparatus according to claim 1, wherein said cannula includes a
duct connected to said gas source, said enlarged member comprising
means for being removably coupled to the duct.
7. An apparatus according to claim 1, wherein said bulbous member
comprises an inflatable and deflatable element and means is
provided for introducing and discharging fluid therefrom, said
element being variable in size by varying the amount of fluid
therewithin.
8. A nasal cannula for conducting therapeutic gas to one nasal
cavity of a patient comprising:
a flexible gas duct for conducting therapeutic gas, and
a single resilient bulb mounted on said gas duct intermediate its
ends,
said bulb being of generally spherical configuration to fit snugly
within and against the wall of the nasal vestibule of said one
nasal cavity to form an air seal during inhalation and exhalation
by the patient,
said bulb including a passage extending therethrough and
terminating at an outer wall thereof and communicating with said
gas duct for conducting therapeutic gas to said one nasal
cavity.
9. Apparatus according to claim 8, wherein said bulb comprises an
inflatable and deflatable element, and means provided for
delivering pressurized fluid to inflate said bulb.
10. A nasal cannula for conducting therapeutic gas to one nasal
cavity of a patient comprising:
a flexible gas duct for conducting therapeutic gas, and
a single resilient bulb mounted on said gas duct intermediate its
ends,
said bulb being engageable snugly within and against the wall of
the nasal vestibule of said one nasal cavity to form an air seal
during inhalation and exhalation by the patient,
said bulb including a passage extending therethrough and
terminating at an outer wall thereof and communicating with said
gas duct for conducting therapeutic gas to said one nasal
cavity.
11. A method of administering therapeutic gas to a patient
comprising the steps of providing a seal-forming member within one
nasal vestibule of the patient in gas sealing relationship with the
inner wall of such vestibule, communicating the other nasal
vestibule with ambient surroundings and conducting the gas inwardly
along a passage through the seal-forming member during an
inhalation stroke of the patient, so that the gas is inhaled solely
through said one nasal vestibule and into the patient's lungs and
exhaled solely through the other nasal vestibule and/or open mouth
of the patient.
12. A method according to claim 11, wherein said providing step
comprises compressing a resilient bulbous member and inserting the
compressed bulbous member into the nasal vestibule whereupon it
expands to a larger size.
13. A method according to claim 1, wherein said providing step
comprises inflating an inflatable-deflatable bulbous member by
means of a separate fluid duct communicating with said bulbous
member.
Description
BACKGROUND AND OBJECTS OF THE INVENTION
The present invention relates to methods and apparatus for
administering therapeutic gaseous substances into the nostril of a
patient.
In the medical treatment of patients it is often necessary to
delivery oxygen or other therapeutic gaseous substances to the
patient's respiratory system. This has been heretofore achieved by
means of nasal cannulas such as the type disclosed in U.S. Pat. No.
2,868,199 issued to Hudson on Jan. 13, 1959, and U.S. Pat. No.
3,726,275 issued to Jackson et al on Apr. 10, 1973.
In the medical treatment of patients it is also sometimes necessary
to perform a surgical operation called tracheostomy or to perform
endotracheal intubation, both of which involve significant risks.
Among the purpose of these procedures is to eliminate a portion of
dead space rebreathing of exhaled air containing carbon dioxide.
There is presently no known way for reducing dead space ventilation
other than endotracheal intubation or perform a tracheostomy.
Some nasal cannulas heretofore employed have comprised a flexible
duct which is to be connected to a source of pressurized gas to be
administered. A pair of short tubes communicate with the duct and
are loosely received within the nasal cavities of the patient. When
installed, the tubes are able to conduct gas from the duct to the
nasal cavities, whereupon the gases are inhaled and exhaled by the
patient.
The inhaled gases, which may comprise a mixture of room air and
therapeutic gas, travel through each nasal cavity, and into the
pharynx. The inhaled gases fill all voids and recesses within the
nasal cavities before reaching the pharynx. Such voids may be
considered "dead space" because the gases therein at the end of
inhalation never reach the gas exchange areas of the lung, and are
discharged during subsequent exhalation. It will be appreciated,
then, that much of the inhaled gas will merely occupy the dead air
spaces, rather than reach the gas exchange areas of the lung (i.e.,
the alveoli) to be of therapeutic benefit to the patient.
It can be understood that during exhalation, normally exhaled air
with an increased carbon dioxide level (carbon dioxide produced in
the body is a waste product of respiration) is exiting through the
nasal and/or oral passages thus filling these cavities at the very
end of exhalation. This spent respiratory air must necessarily be
re-inhaled before and ahead of any therapeutic gas and/or ambient
air.
Of course, the effects of dead air space can be reduced by
tracheotomy or intubation which bypasses some of the dead space but
such procedures involve significant risk and discomfort not present
when using a cannula-type instrument, such as is an object of this
invention. Conventional oxygen therapy cannulas do nothing to
reduce the effects of dead space rebreathing. Breathing masks have
also been employed, however, such masks actually increase effective
dead air space, are relatively uncomfortable to the patient, and
must be removed when eating, expectorating, etc., all of which
demonstrates the need for new and improved methods and apparatus
for administering therapeutic gases.
Thus, the only known effective ways of reducing the amount of dead
space carbon dioxide the patient needs to re-inhale comprise
hazardous tracheostomy or endotracheal intubation operations.
Another problem involved with the delivery of therapeutic gas via
conventional nasal oxygen cannulas occur when the patient
"mouthbreaths", i.e., has his mouth open during breathing. In such
instances a substantial portion of the breathing action will be
applied through the mouth rather than through the nose, thereby
minimizing the amount of inhalation occurring through the nose.
Accordingly, the therapeutic benefit of the gas thus administered
will as least be greatly reduced. In such instances, reliance is
placed on the chance that small amounts of unspent therapeutic
gases will be exhaled from the nose to a location ahead of the
mouth to be subsequently inhaled through the mouth.
Because a patient may readily change from nose breathing to mouth
breathing and back again, the amount and concentration of
therapeutic gas reaching his lungs varies greatly.
It is therefore, an object of the invention to minimize or obviate
problems of the above-discussed type.
It is a further object of the invention to maximize the therapeutic
benefit to a patient of nasal-supplied gases.
It is an additional object of the invention to provide methods and
apparatus for administering the therapeutic gas through a patient's
nose in a manner minimizing the effects of rebreathing of carbon
dioxide laden dead space air within the nasal and/or oral
cavities.
It is another object of the invention to minimize the amount of
dead space carbon dioxide inhaled by a patient without the need for
tracheostomy or endotracheal intubation.
It is an additional object of this invention to provide new, and
more efficient and comfortable means of administering therapeutic
gases in high concentration than with presently employed oxygen
therapy masks.
SUMMARY OF THE INVENTION
These objects are achieved by the present invention which involves
a nasal cannula of the type to be connected to a fluid duct and
positioned within the nose of a patient for administering
therapeutic fluid. The cannula comprises a resilient bulbous member
configured to fit snugly within and against the vestibule wall of
one nasal cavity of the patient to form a tight seal with respect
thereto while maintaining the other nasal cavity in communication
with ambient surroundings. The bulbous member includes a passage
therethrough for communicating the fluid duct with the one nasal
cavity so that fluid supplied through the duct is inhaled through
the one nasal cavity and exhaled through the other nasal and/or
oral cavities.
BRIEF DESCRIPTION OF THE DRAWING
Other objects and advantages of the invention will become apparent
from the following detailed description of a preferred embodiment
thereof in connection with the accompanying drawings in which like
numerals designate like elements, and in which:
FIG. 1 is a perspective view of a cannula according to the present
invention;
FIG. 2 is a longitudinal sectional view taken through a first type
of bulbous portion of the cannula,
FIG. 3 is a longitudinal sectional view taken through a second type
of bulbous portion of the cannula;
FIG. 4 is a longitudinal sectional view taken through a third type
of bulbous portion of the cannula;
FIG. 5 is an interior side view of a patient's head, depicting the
bulbous portion of the cannula in snug fit with the wall of one
nasal vestibule;
FIG. 6 is a front view of a patient's nose with the cannula
installed therein;
FIG. 7 is a longitudinal sectional view through the bulbous portion
of a second embodiment of a nasal cannula according to the present
invention;
FIG. 8 is a front view depicting the cannula of FIG. 6 disposed in
a patient's nose;
FIG. 9 is a side view of a third embodiment of a nasal cannula
according to the present invention;
FIG. 10 is a side view through a patient's head depicting the
manner in which the nasal cannula of FIG. 9 is installed;
FIG. 11 is a cross-sectional view taken along line 11--11 of FIG.
9; and
FIG. 12 is a longitudinal sectional view of the bulbous end of the
cannula of FIG. 9.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
A preferred nasal cannula 10 according to the invention is depicted
in FIG. 1 and comprises a gas duct 12 formed of a suitable flexible
material such as plastic. The ends of the duct 12 are mounted
within a common fitting 14. Therapeutic gas is supplied
continuously at a set flowrate through the fitting to both ends of
the duct under a slight pressure which is conventional in
treatments of this sort. The duct 12 is configured to encompass the
neck of a patient.
Situated intermediate the ends of the duct is a bulbous member 16
from which the gas is to be administered to the patient P. The
bulbous member is configured to fit snugly within the vestibule 18
of a nasal cavity 20, as depicted in FIG. 5. Preferably, the
bulbous member 16 is of generally spherical configuration and is
formed of a highly flexible material. For example, the bulbous
member may be formed of a soft plastic material or, as depicted in
FIG. 3, of a rubber or foam rubber center 22 with a plastic or
rubber or other type of elastic skin 24 thereover (the skin serving
to minimize friction during insertion into the nasal vestibule, to
assure a fluid tight seal, or to provide for adjusting the size of
the bulbous member).
The bulbous member may be formed integrally with the gas supply
duct (FIG. 2), or it can be joined thereto as a separate component
(FIG. 4). In the latter case, the bulbous member 16A may include a
pair of tubular sleeves 26 which receive the ends of gas supply
ducts 12A, B. The joining of the bulbous member and ducts 12A, B
can be achieved in such manner that the bulbous member 16A is
replaceable relative to the ducts.
Extending through the bulbous member is a central passage 30 (FIG.
2) which communicates at an inner end with the gas supply duct 12.
Preferably, the passage 30 is of progressively larger
cross-sectional area toward the outer end, to facilitate the travel
of gas therethrough.
The bulbous member 16 can be installed within the nasal vestibule
18 by being manually compressed during insertion and then released
for expansion within the vestibule. The bulbous member is sized
slightly larger than the cross-sectional area of the nasal
vestibule 18 so that the bulbous member tightly engages the inner
walls of the vestibule 18. Due to the flexibility and elasticity of
both the bulbous member 16 and the walls of the nasal vestibule 18,
each is able to conform to the shape of the other and assure that a
tight air seal is formed around the bulbous member during
inhalation and exhalation by the patient.
IN OPERATION, the patient inhales through both nostrils 20, 32
(FIG. 6). Therapeutic gas only is being inhaled into the nostril
with the bulbous member at a set flowrate while any additional gas
to supply the patient's total inhalation flow rate must enter the
other nostril open to ambient air. Since no appreciable air leakage
occurs around the bulbous member, that portion of the breathing
effort applied to the bulb-containing nasal cavity will receive
only therapeutic gas from the bulb passage 30. (The total amount of
therapeutic gas which is inhaled will be significantly greater than
that normally inhaled from a conventional loose-fitting cannula due
to the simultaneous inhalation of therapeutic gas which has filled
and replaced dead space air in the other nasal cavity during the
preceding exhalation.) The inhaled therapeutic gas from the dead
air spaces within nasal passages enters the pharynx. During
exhalation, all gas/air discharge occurs through the other, open
nasal cavity 32 (exhalation through the bulb-containing nasal
cavity is prevented by the air seal established by the bulbous
member 16). During exhalation and during the slight pause following
the very end of exhalation, therapeutic gas continues to flow into
the nostril with the cannula and exits through the other nostril
along with gas being exhaled from the lungs. In this way, expired
air in the dead space is being washed out and replaced with
therapeutic gas. The dead space now becomes a reservoir of
therapeutic gas, rather than exhaled air, to be rebreathed. Thus,
all unspent therapeutic gases occupying the dead air spaces in both
nostrils at the end of exhalation remain, and are thereby
positioned ahead of the subsequent inhalation of therapeutic gases
and/or ambient air drawn-in during the ensuing inhalation.
Accordingly, such unspent gases in the dead air spaces will be
drawn-into the pharynx and will also mix with the charge of
therapeutic gas from the cannula.
It will be appreciated that the air seal formed by the bulb 16
assures that all of the breathing effort which is applied to the
bulb-containing nasal cavity 20 acts upon the incoming therapeutic
gas (i.e., no ambient air is inhaled through that nostril which
would dilute the therapeutic gas). This seal assures that the
entire quantity of therapeutic gas administered will be delivered
into the nasal cavity 20. This seal also assures that while
therapeutic gas continues to flow during exhalation, it must enter
and fill the other nostril from within before exiting through that
nostril to the ambient surroundings. This means that the patient
has no choice but to inhale these physiological reservoirs (dead
spaces) of therapeutic gas ahead of and before any ambient air
which may serve to dilute it. This method and apparatus makes it
mandatory for the patient to breath the gas in the amounts being
administered and thus affords a much more exacting control of what
concentration the patient receives. Such quantity is appreciably
greater than that normally inhaled into the nasal cavities from a
conventional loose-fitting cannula. The significance of this fact
will be appreciated when considering that the inhaled therapeutic
gas from the bulbous member of the present invention is subject to
mixing with exhaled gas in the dead air spaces of neither of the
nasal cavities. The effects of the dead air spaces of the open
nasal cavity 32 is, in effect, nullified since it is used as a
physiological reservoir for therapeutic gas yielding an increase in
the amount and therefore concentrations of therapeutic gas reaching
the lung and essentially washing out and replacing carbon dioxide
laden air with therapeutic gas containing no carbon dioxide.
In the case of mouth-breathing (discussed earlier) wherein a
reduced amount of breathing takes place through the nose,
therapeutic gas enters the pharynx and fills the oral cavities
during exhalation similar to the way in which the open nostril
functions so that all dead space cavities including the open mouth
are essentially filled with therapeutic gas during exhalation and
just before inhalation commences. This is an improvement over
conventional loose-fitting cannula tubes in which little, if any,
unspent therapeutic gas remains and fills the nasal and/or oral
cavities following exhalation.
It will be appreciated that numerous modifications and embodiments
are possible within the scope of the invention. For example, a
cannula 33 comprising a pair of bulbous members 16, 34 can be
provided for insertion into both nasal vestibules (FIGS. 7-8). A
passage 36 through one of the bulbous members 34 communicates with
ambient surroundings to enable the patient to exhale. By inserting
two bulbous members into the nose, the intensity of attachment of
the therapeutic device to the nose is increased.
Another embodiment of the invention is illustrated in FIGS. 9 and
12. A cannula 40 comprises a gas duct 42 to the end of which is
mounted a closed membrane 44. The membrane is formed of a soft
resilient material and forms a resilient bulbous component which
can be inflated or deflated by means of a fluid passage 46, the
latter communicating with the confined space 48 formed by the
membrane. Pressurized gas or liquid is supplied to the passage 46
in any suitable fashion (e.g., from a syringe) to inflate the
membrane before and/or after insertion into the nostril. The size
of the bulbous component can be easily varied to suit the
particular patient. The passage 46 can be valued to enable the
bulbous component to be easily deflated. The walls of the duct 42
are made thick enough to prevent collapsing of same when the bulb
is inflated. The bulb can be partially inflated before insertion
and then fully inflated after insertion, so as to make insertion
more comfortable while maximizing the intensity of the fluid
seal.
Although the invention has been described in connection with a
preferred embodiment thereof, it will be appreciated by those
skilled in the art that additions, modifications, substitutions and
deletions not specifically described may be made without departing
from the spirit and scope of the invention as defined in the
appended claims.
* * * * *